<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
  </head>
  <body>
    <script>
      const arr1 = ["a", "b", "c"];
      const arr2 = ["d", "e", "g"];
      const arr3 = [1, 2, 3];
      const arr4 = ["css", "html", "js"];
      console.log(arr1.concat(arr2, arr3, arr4));
      console.log(arr2.concat(arr2, arr3, arr4));
      console.log(arr4.concat(arr2, arr3, arr1));
      console.log(arr1.concat(arr2, arr3, ["vb", "c++"], 100));
      console.log(arr4.concat([])); //复制数组
      console.log([].concat(arr4)); //复制数组
    </script>
  </body>
</html>
